Portable motor-driven hack saw



' Sept. 16,. 193). -r. E. SINCLAI 1,776,173

PORTABLE MOTOR DRIVEN HACK SAW Filed Sept. 2, 1927 SSheets-Sheet 1 W N fkamaszi yzrwlaig Ilrrm-Iss: ATTORNEY Sept. 16, 1930.- c 1,776,173

PORTABLE MOTOR DRIVEN HACK SAW Filed Sept. 2, 1927 3 Sheets-Sheet 2 3710MB iTa'ZaZ'T;

INVENTOR WITNESS: i ATTORNEY $P 16', 1930- T. E. SINCLAIR I 1,776,173 PORTABLE ko'roR DRIVEN HACK SAW I Filed Sept. 2, 192'? a sheets-sheet s C RB, Illllllllll a P E L a I L irwlaz' M aW wnusss; ATTORNEY Patented Sept. 16, 1930 UNITED STATES PATENT OFFICE PORTABLE MOTOR-DRIVEN HACK SAW Application filed September a, 1927. Serial no. 217,210.

This invention relates to a motor driven hack saw, the general object of the invention being to provide a device of this nature which can be easily transported from place to place and which can be operated by a small motor using ordinary current, with means for breaking the circuit of the motor as soon as the blade cuts through the work piece, such means also holding the circuit open when the hack saw is in a lowered position.

Another object of the invention is to provide means at the front end of the device for controlling clutch means on the driven shaft so that the operator can easily throw the saw out of operation without stopping the motor, as he stands in front of the device.

A still further object of the invention is to so arrange the parts that the devicewill need but little attention on the part of the operator after the device starts to actuate.

This invention also consits in certain other features of construction and in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawings and specifically pointed out in the appended claims.

In describing my invention in detail, reference will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which v Figure 1 is an elevation looking toward one side of the device.

Figure 2 is a similar view of the opposite side thereof. 7

Figure 3 is a plan view.

Figure 4 is a View of one end of the device.

Figure 5 is a view of the opposite end 7 thereof.

Figure 6 is a section on line 6-6 of Figure 3.

Figure 7 is a diagrammatic view of the circuit.

In these views, 1 indicates a table or frame/ 5 which supports the small frame 2 and the support 3 for the clamp 4 which holds the work piece A in position, the handle 5 of the clamp extending to a point in front of the table. Shafts 6 and 7 are journaled in the frame 2 and the shaft 6 carries a pulley 8 and a pinion 9, the pinion 9 meshing with a gear 10 rotatably mounted on the shaft 7 and having a clutoh part for engaging a sliding clutch part ll keyedito the shaft 6, this latter part being moved into operative and inoperative position through means of a clutch fork 11 to which is connected a bell crank 12 pivoted to the under sideof the table and to the outer end of which is pivoted a rod 13 which extends under the table and has its outer end extending beyond the front end of the table so that an operator standing at the front end of the device can shift the clutch by moving the rod.

A motor M is arranged under the table and is supported on a shelf carried by the table and a belt 14 passes over a pulley on the motor shaft and over the pulley 8 so that the shaft 6 will be driven from the motor.

A guiding member 15 is pivotally supported by the frame 2 by having its depending ear 16, arrangedat the rear end of the mem ber 15, pivoted to a part of the frame. A bar 17 is slidably supported in the member 15 and the hack saw frame 18 is fastened to this bar. The'blacle of the saw is shown at 19.

A crank 20 is secured to one end ofthe shaft 7 and a pitman 21 connects the crank with the frame 18 so that the rotary movement of the shaft 7 is transmitted tothe hacksaw frame to impart a .reciprocatory motion to the frame.

A lever 22 is pivotally supported on the table and carries a switch 23 for bridging a pair of contacts 24 arranged in the'circuit A 853 of the motor M. The switch is normally held in closed position by means of a spring 25 engaging a lever and an adjustable post 26 is carried by the lever and is arranged under the member 15 so that when said member drops, it will strike said post and thus tilt the lever and move the s'witch23 off the contacts 24 and thus break the circuit of the motor. The circuit is p'rovide'dwith a hand operated switch B.

From the foregoing it will be seen that when the motor is in operation, the shaft 6 will be driven and this movement will be imparted to the gear 10 and if the clutch is in operative position, the shaft 7 will also be driven so that the hack saw will be reciprocated by the rotary movement of the crank, the saw being guided in its movement by the member 15. If, for any reason, the 5 operator wishes to stop the action of the saw, he would simply shift the clutch by means of the rod 13-so as to stop the rotary movement of the shaft 7. When the saw cuts through the work piece, the downward movementof the parts will break the circuit to the motor and this circuit will also-be broken when the saw is in its lowest position. By providing the clamp for the work pieceand the means for automatically stoppingv the. 15 device when the saw has passed through the workv piece,.the operator, after starting the saw into operation, can leave, as the device will need no further action as it, will stop itselfas soon as the saw passes through the 2'0 work piece. As willbe seen, the device is small enough to enable it to'be transported from place to place as-desired.

It is thought from the foregoing description that the advantagesand novel features of my invention will be readily apparent.

I desire it' to be understood that I may make changes in the construction and in the combination and arrangement of the several parts, provided that such changes fall within tllGSOOPB of the appended claim.

What I claim is-:--

A portable motor driven hack saw comprising a table adapted to support a light weight electric motor to be connected to an electric source, a work holder'onsaid table, a support on the table, a power shaft journaled to said support and driven by the motor, a driven shaft carried by the support, a means for'connecting said shafts, a crank at oneend of the 40 driven shaft,,. a pitman connected to said crank and to the frame of a hack saw for cutting material supportedby the work holder, a guide'sleeve having one end pivoted to the support and its other end free to move 5 upwardly and downwardly with respect to the work holder,- a guide member slidable in said sleeve and connected to the frame of the hack saw, contacts carried by the table under the free end of the sleeve and in circuit with so the motor and electrical source, anda spring pressed and pivotally mounted contact arm carried by the table and adapted to normally bridge the contacts to complete the circuit to the motor and to be engaged and moved by the. guide sleeve todisengage the contact and break the circuit to the motor when the hack saw passes. completely through the material on the work holders In: testimony whereof I- aflix' my signature.

6G THOMAS E. SINCLAIR. 

